* added cmd line script to read out and set flow control (red-y series by Voegtlin)
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Markus Rosenstihl
parent
6dc67edaaf
commit
50b6bf6622
210
src/tools/flow_control.py
Executable file
210
src/tools/flow_control.py
Executable file
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#!/usr/bin/env python2
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# -*- encoding: utf-8 -*-
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import optparse
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import os, sys
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import serial
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import numpy as N
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import struct
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import binascii
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import time
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DEBUG = False
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"""
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6.2.2 CRC Generation
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====================
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The Cyclical Redundancy Checking (CRC) field is two bytes, containing a 16–bit binary value. The CRC value is calculated by the
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transmitting device, which appends the CRC to the message. The device that receives recalculates a CRC during receipt of the
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message, and compares the calculated value to the actual value it received in the CRC field. If the two values are not equal, an error
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results.
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The CRC is started by first preloading a 16–bit register to all 1’s. Then a process begins of applying successive 8–bit bytes of the
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message to the current contents of the register. Only the eight bits of data in each character are used for generating the CRC. Start
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and stop bits and the parity bit, do not apply to the CRC.
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During generation of the CRC, each 8–bit character is exclusive ORed with the register contents. Then the result is shifted in the
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direction of the least significant bit (LSB), with a zero filled into the most significant bit (MSB) position. The LSB is extracted and
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examined. If the LSB was a 1, the register is then exclusive ORed with a preset, fixed value. If the LSB was a 0, no exclusive OR takes
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place.
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This process is repeated until eight shifts have been performed. After the last (eighth) shift, the next 8–bit character is exclusive ORed
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with the register’s current value, and the process repeats for eight more shifts as described above. The final content of the register,
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after all the characters of the message have been applied, is the CRC value.
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A procedure for generating a CRC is:
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1. Load a 16–bit register with FFFF hex (all 1’s). Call this the CRC register.
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2. Exclusive OR the first 8–bit byte of the message with the low–order byte of the 16–bit CRC register, putting the result in the
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CRC register.
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3. Shift the CRC register one bit to the right (toward the LSB), zero–filling the MSB. Extract and examine the LSB.
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4. (If the LSB was 0): Repeat Step 3 (another shift).
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(If the LSB was 1): Exclusive OR the CRC register with the polynomial value 0xA001 (1010 0000 0000 0001).
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5. Repeat Steps 3 and 4 until 8 shifts have been performed. When this is done, a complete 8–bit byte will have been
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processed.
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6. Repeat Steps 2 through 5 for the next 8–bit byte of the message. Continue doing this until all bytes have been processed.
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7. The final content of the CRC register is the CRC value.
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8. When the CRC is placed into the message, its upper and lower bytes must be swapped as described below.
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Placing the CRC into the Message
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When the 16–bit CRC (two 8–bit bytes) is transmitted in the message, the low-order byte will be transmitted first, followed by the high-
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order byte.
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"""
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crc_test = "\x0d\x01\x00\x62\x00\x33"
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crc_expected = 0xddd
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def crc(message):
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crc = 0xffff # step 1
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for byte in message:
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if type(byte) == type(str):
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crc ^= ord(byte) # step 2: xor with lower byte of crc
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else:
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crc ^= byte # step 2: xor with lower byte of crc
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for i in range(8): # step 5: repeat 2-4 until 8 shifts were performed
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if (crc & 0x1) == 0: # step 4: check LSB
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mask = 0x0
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else:
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mask = 0xa001
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crc >>= 1 # step 3: shift one bit to the right
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crc ^= mask
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if DEBUG: print "Message:", [i for i in message], " CRC:", hex(crc)
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return chr(crc & 0xff) + chr(
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(crc >> 8) & 0xff) # return lower byte, upper byte (shift to the right, return last byte) i
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class Flow:
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def __init__(self, device="/dev/ttyUSB0"):
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self.s = serial.Serial(port=device, timeout=0.02)
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self.s.readline()
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self.s.timeout = 0.2
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self.address = bytearray([0x3])
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self.rcommands = {
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"flow": [bytearray([0x3, 0x0, 0x0, 0x0, 0x2]), ">f"],
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"temperature": [bytearray([0x3, 0x0, 0x2, 0x0, 0x2]), ">f"],
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"setflow": [bytearray([0x3, 0x0, 0x6, 0x0, 0x2]), ">f"],
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"total": [bytearray([0x3, 0x0, 0x8, 0x0, 0x2]), ">f"],
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"alarm": [bytearray([0x3, 0x0, 0xc, 0x0, 0x1]), ">H"],
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"hwerror": [bytearray([0x3, 0x0, 0xd, 0x0, 0x1]), ">H"],
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"unit_flow": [bytearray([0x3, 0x0, 0x16, 0x0, 0x4]), ">8s"],
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"medium": [bytearray([0x3, 0x00, 0x1a, 0x0, 0x4]), ">8s"],
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"device": [bytearray([0x3, 0x00, 0x23, 0x0, 0x4]), ">8s"],
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"unit_total": [bytearray([0x3, 0x40, 0x48, 0x0, 0x4]), ">8s"],
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}
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self.wcommands = {
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"flow": [bytearray([0x06, 0x0, 0x6]), ">f"]
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}
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def send_data(self, data_and_type):
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data, type = data_and_type
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if DEBUG: print "send", data_and_type, "data:", binascii.hexlify(data), "type:", type, self.address
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msg = self.address + data
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msg_crc = msg + crc(msg)
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if DEBUG: print "send:", repr(str(msg_crc))
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nbytes_sent = self.s.write(str(msg_crc))
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if DEBUG: print "send:", self.s
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if DEBUG: print "Sent bytes:", nbytes_sent
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time.sleep(0.1) # this is necessary, otherwise no data can be received
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return msg_crc
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def recv_data(self):
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"""
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Reading Data
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============
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Function: 0x3
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Format of the resulting string
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Addr Func NoBytes Byte1...N CRCHi CRCLo
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"""
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message = bytearray(self.s.read(3))
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if DEBUG: print "recv_data: header:", binascii.hexlify(message)
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if message == "":
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return
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addr, func, nbytes = message
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if func == 0x03:
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data = self.s.read(nbytes)
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if DEBUG: print "recv_data: data: %i %s" % (nbytes, binascii.hexlify(data))
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message += data
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crc_data = self.s.read(2)
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if DEBUG: print "recv_data: crc", repr(str(crc_data))
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if crc(message) != crc_data:
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print "mismatch", crc(message), crc_data
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return data
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def get_var(self, named_type="flow"):
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cmd,fmt = self.rcommands[named_type]
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if DEBUG: print "get_var", cmd,fmt
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self.send_data([cmd,fmt])
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d = self.recv_data()
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if d:
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d = struct.unpack(fmt, d)[0]
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return d
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# msg = self.recv_data()
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# print str(msg)
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# float struct.unpack('>f', "4byte string")
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# ushort struct.unpack('>H', "2byte string")
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def current_flow(self):
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# start register 0x0000
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# 2 bytes
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cmd = self.address + bytearray([0x3, 0x0, 0x0, 0x0, 0x2])
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return cmd + crc(cmd)
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def current_temperature(self):
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# start register 0x0002
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#
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#
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cmd = self.address + bytearray([0x3, 0x0, 0x2, 0x0, 0x2])
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return cmd + crc(cmd)
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def set_flow(self, flow):
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"""
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write multiple registers: 0x10
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startHi
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startLo
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numregHi
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numregLo
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numbytes
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"""
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_flow = struct.pack(">f", flow)
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# cmd = address + bytearray([0x10,0x0,0x6, 0x0, 0x2, 0x2]) + _flow
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cmd1 = self.address + bytearray([0x06, 0x0, 0x6]) + _flow
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self.s.write(cmd1 + crc(cmd1))
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time.sleep(0.01)
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# print self.s.readline()
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# self.recv_data()
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def cmd(self, data):
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cmds = self.address + data
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for i in cmds:
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print hex(ord(i)),
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return cmds + crc(cmds)
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if __name__ == "__main__":
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conf = os.path.expanduser('~/.flow')
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if os.path.exists(conf):
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dev = open(conf).readlines()[0].strip()
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redy = Flow(device=dev)
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print "Device: %6s" % (redy.get_var("device"))
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print "Medium: %6s" % (redy.get_var("medium"))
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print "Current Flow: %6.2f" % (redy.get_var("flow"))
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print "Current Set Flow: %6.2f" % (redy.get_var("setflow"))
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print "Flow Unit: %6s" % (redy.get_var("unit_flow"))
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print "Total Gas: %6.2f" % (redy.get_var("total"))
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print "Total Unit: %6s" % (redy.get_var("unit_total"))
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print "Current Temperature: %6.2f C" % (redy.get_var("temperature"))
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print "Alarm: %8i" % (redy.get_var("alarm"))
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print "HW Error: %8i" % (redy.get_var("hwerror"))
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if len(sys.argv) > 1:
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try:
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float(sys.argv[1])
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except:
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raise SyntaxError, "usage: %s <flow> # to set flow or empty to get current flow\nfirst line in ~/.flow defines serial tty, default: /dev/ttyUSB0" % (sys.argv[0])
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print "Set flow: %6.2f"%(float(sys.argv[1]))
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redy.set_flow(float(sys.argv[1]))
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